Slack adjuster for railway car brake equipment



7 Feb. 16, 1932. H. E. ANDERSON SLACK ADJUSTER FOR RAILWAY CAR BRAKE EQUIPMENT Original Filed March 21, 1930 2 Sheets-Sheet l ATTORNEY Feb. 16, 1932. H. E. ANDERSON ,SLACK ADJUSTER FOR RAILWAY CAR BRAKE EQUIPMENT Original Filed March 21. 1930 2 Sheets-Sheet 2 ATTORNEY Patented Feb. 16, 1932 UNITE STATES PATENT OFFICE HARLEY E. ANDERSON, OF KANSAS CITY, MISSOURI, ASS IGNOR T GUSTIN-IBACON MANUFACTURING ('30., 01" KANSAS CITY, MISSOURI, A CORPQRATION OF MISSOURI SLACK ADJUSTER FOR RAILWAY GAR BRAKE EQUIPMENT Original application filed March 21, 1930, Serial No.

437,653. Divided and this application filed July 9,

,1930. Serial No. 466,842.

My invention relates more'particula-rly to brakes which are operated by compressed air or vacuum, and this application is a division of my application filed March 21, 1930, Serial No. 437,653, which resulted in Patent No.

1,77 2,433, issued August 5, 1930.

The object of my invention is the provision of means whereby the air brake piston travel is automatically maintained between predew termined limits, regardless of the degree of wear onthe brake shoes, thus making it possible for a braking application to be uniformly made throughout the length of a train.

Still another object of theinvention is, to

provide a device which, although strong, durable, eficient and inexpensive, can be very light in construction, because of locating it on the top rod of the brake structure.

A further object of my invention is, to provide a device which will shorten the top rod, rather than move the brake cylinder levers.

Another object of the invention is, to provide a construction which willat all times maintain the brake cylinder levers at a right angled position with relation to the center line of the brake cylinder, thereby avoiding the dangerof the brake rigging fouling on the car wheels or the car frame.

A concreteembodiment of my invention is illustrated in the accompanying drawings, which are to be considered as a part of this specification, in which Fig. 1 is aphantom top plan view through the floor of a freight car, to indicate the brake rigging and parts of the invention;

Fig. 2 is a side view of the car as shown in Fig. 1;

Fig. 3 is an enlarged central vertical sectional view through the take-up apparatus;

Fig. 4 is an end view of the same; and

Fig. 5 is a diagrammatic view of a slightly modified form of take-up.

Similar reference numerals refer to similar parts throughout the entire description.

In the drawings I show the plan view of a clamped relation by clamping bolts 32. The

freight car, with floor 1, wheels 2, brake shoes 3, dead levers 4 of each truck, lower rods 5 connecting the dead levers 4 with floating truck levers 6, top rods 7 and 8 connected to floating cylinderlever 9 and dead lever 10, cylinder lever rod 11, and brake push rod 14. The brake push rod 14 is connected to air brake piston 14 slidingly mounted within air cylinder 15, the latter and its air reservoir 16 being securely supported below the floor 1 in any suitable manner. All the parts just enumerated are standard equipment on rail way cars as now constructed.

In order, therefore, to provide mechanism cooperating with the brake rigging, whereby the wear on the brake shoes 3 may be automatically compensated,and an optimum piston travel and manual chain wrap-up be maintained, the end of the dead lever 10,-instead of being fulcrum'ed on the car frame asin standard practice, is fulcrumed to the end of a longitudinally movable fulcrum arm or rack bar 28.

Secured to the under side of the car floor 1, orvto any other fixed point of support, is an air cylinder 29, closed at one end by a pressure head 30, and at its other end by a non-pressure head 31, said heads and cylinder being formed with circumferential aligned flanges held in cylinder 29 is formed integrallywith a supporting flange or base 33, whichis bolted to theunder side of the car floor 1, as shown in Fig. 2, said base 33 being formed with a passageway 34 in which the rack bar 28 is slid-' ingly mounted. I v

Fitted within the cylinder 29 is a piston 35, said cylinder29 having an air port 36 in front of the piston, connected by a pipe 37 to the air cylinder 15 of the car brake. The piston 35 is normally held in position by an ex pansion spring 38, fitted between the back of the piston 35'and the non-pressure head 31 Rigidly fastened to the piston 35, and projecting through the non-pressure head 31, is a piston rod 39, provided on its end with a housing 40, having vertical and horizontal intersecting passageways for the respective reception of a dog 41, advanced by a spring 42, and the rack bar 28. The end of the dog 41 is designed so that it shall engage teeth 43 formed on the under side of said rack bar 28.

The pressure head 30, at the opposite end of the cylinder 29, is formed integrally with a housing 44, substantially conforming to the housing 40, except that it terminates flush with the under side of the rack bar 28, and therefore does not engage or encircle said rack bar 28. Mounted in said housing 44 is a dog 45, adapted to be advanced by a spring 46, for engagement with the teeth 43 of the rack bar 28.

By reference to Figs. 3 and 4, it will be noted that the rear end of the rack bar'28 is formed with a downwardly-projecting stop lug 47, for engagement with the end of the housing 44 as illustrated, to prevent the rack bar 28 from being advanced too far inwardly under conditions that will hereinafter appear. In order to permit the device to be assembled or dismounted, the housing 40, the non-pressure head 31, and the exterior of the cylinder 29, are all formed with an aligned groove 48, through which the stop lug 47 may pass.

In order that the device may be conveniently assembled and dismounted, the dogs 41 and 45 are each provided with a stem 49 projecting through the bottom of their respective housings, whereby an operator may retract the dogs 41 and 45 to free the rack bar 28 for manual operation of the brake rigging, so that slack may be gained when it is desired to replace the brake shoes 3.

The rack bar 28 and cylinder 29 may be designed to take up slack by inches, or in fractions thereof, but for freight car use the removal of slack in inch steps has been found to be a sufiiciently fine adjustment, the length of the rack bar 28 being such as to accommodate the maximum piston travel beyond a predetermined or optimum travel. For example, in the construction as illustrated, the maximum piston travel is 12 inches, and the desired or optimum travel is 5% inches. As the rack bar 28 is adjusted in steps of one inch, the pipe 37,1cading to the cylinder 29, is tapped into the cylinder 15 at a point 6% inches from the pressure head of said lastnamed cylinder; thus the travel of the air brake piston is maintained between inches and 6 inches.

With the construction described, it will be apparent that as long as the brake shoes 3 are substantially new, and the air brake piston does not travel (5 inches, the port leading to the air pipe 37 is not uncovered, and the adjusting air cylinder 29 does not function. However, when wear occurs in the brake shoes 3, and the air brake piston travels 6 4 inches, a part of the air in said cylinder passes through the pipe 37 and enters the cylinder 29. Entry of air into said cylinder 29 projects the piston 35, and moves the housing to the left on the rack bar 28 a sufficient distance for its dog 41 to engage the next tooth 43 of said rack bar 28, the yokes on the end of said rack bar 28, to which the dead lever 10 is pivoted, remaining stationary during the outward travel of the dog 41, as the rack bar 28 is held by the rearmost dog 45.

Upon release of the air from the air brake cylinder 14, the brake piston 35 will, on its reverse movement, uncover the pipe 37 and permit the air in the cylinder 29 to exhaust. The spring 38 now expands and, as it reversely moves the piston 35, effects movement of the rack bar 28 to the right (as illustrated in Fig. 3), as the dog 41 has entered another tooth 43, the dog 45 being depressed upon movement of the rack bar 28 until another tooth 43 is in alignment. The fulcrum point at the end of the dead lever 10 is moved a distance equivalent to the length of a tooth 43, thus shortening the travel of the brake rigging necessary to place the brake shoes 3 in full brake-applying position.

With the parts constructed as above described, the rack bar 28 will be retracted one step (one inch), and the piston travel consequently returned to its original travel 5% inches, every time the wear on the brake shoes 3 is such as to permit the piston travel to attain 6 inches, the point of connection of the pipe 37. It will also be understood that the maximum piston travel is governed by the point at which cylinder 15 is tap ed, and that the rack bar 28 may be designed to take up the slack in large or small steps, depending on whether a coarse or a fine adjustment is desired.

Fig. 5 illustrates a modified form of takeup, in which the air brake cylinder 29 is not used. The housing 40 carrying the dog 41 is connected, by a rod 51 having a slotted connection 52, to the floating lever 9. It will be evident that each time the floating lever 9 moves beyond the distance accommodated by the slotted connection 52, the rod 51 will be pulled, and the housing 40 and dog 41 will be advanced on the rack bar 28, and upon release of the air in the cylinder 15, the expansion spring (not shown) within the cylinder 15, corresponding to the expansion spring 38 in the cylinder 29, will retract the rack bar 28. With this construction, a very fine adjustment of the piston travel may be attained, by utilizing a turn-buckle 54 in the rod 51, the piston travel being thus maintained within any desired limits.

Having described my invention, what I regard as new, and desire to obtain by Letters Patent of the United States, is:

The combination with the air brake rigging of a railway car, of a rack bar connected with said rigging, an auxiliary cylinder, a piston in said cylinder, a piston rod secured thereto, a housing rigidly secured to said piston rod, a dog mounted in said housing adapted for successive engagement with teeth of said rack bar, a housing formed on one end of said auxiliary cylinder, a second dog mounted therein which holds the rack against movement, pending the outward movement of the first dog, springs to hold said dogs normally in engagement with the teeth of said rack bar, means to lead fluid pressure from the air brake cylinder to the auxiliary c linder.

HARLEY E. ANDE SON. 

